On 6/4/26 9:37 AM, Ilias Apalodimas wrote:
Currently, the bi_dram[] information is stored in the board info
structure (bd). Because bd is only valid after reserve_board(),
dram_init_banksize() must be called late in the initialization process.
This limitation is problematic, as it forces us to rely on a variety of
bespoke functions to determine board RAM, bank memory sizes, and other
early setup requirements.
By moving bi_dram[] into the global data (gd), we can run it earlier.
This is particularly convenient since boards define their own
dram_init_banksize() routines, which do not always rely on parsing
Device Tree (DT) memory nodes.
Additionally, U-Boot defaults to relocating to the top of the first memory
bank. While boards currently use custom functions to override this
behavior, having the DRAM bank information available earlier in gd makes
relocating to a different bank trivial and standardizes the process.
Regarding the BD, this is likely really old, but it seems BD might be
passed from U-Boot to Linux somehow ? See [1] and U-Boot
include/asm-generic/u-boot.h :
8 * NOTE: This header file defines an interface to U-Boot. Including
9 * this (unmodified) header file in another file is considered normal
10 * use of U-Boot, and does *not* fall under the heading of "derived
11 * work".
Are we certain we are not breaking ABI here ?
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/boot/ppcboot.h
